1. Field of the Invention
The present invention pertains to vehicle barriers and in particular to vehicle barrier posts.
2. Description of the Related Art
Over the years, various devices have been used to guide vehicles along a stretch of road, particularly in areas where a vehicle operator may mixxe2x80x94interpret the course of the roadway due, for example to an abrupt change of direction or a temporary construction work site. Devices used in the past include guard grails, barricades of various sizes to be placed on or near the roadway surface and barrels or the like devices acting as pylons. As pointed out in recent studies culminating in NCHRP 350 guidelines, attention has been focused on roadway or roadside devices which may be inadvertently struck by vehicles traversing the roadway. Such studies are especially concerned with injuries that may result when roadside devices are inadvertently struck by moving vehicles. In general, it has been found desirable to reduce the mass of roadside devices and to alter their construction where possible to reduce or eliminate immovable fixing of the roadside devices. In response to these and other similar concerns, a number of different post constructions have been proposed, which readily deflect when impacted by a moving vehicle. In general, these posts are made to have a much smaller mass than other roadside path-guiding devices, such as barrels and barricade. A number of posts are made flexible by reason of the materials (such as resilient plastic) from which the posts are made (see, for example, U.S. Pat. Nos. 4,343,567; 4,092,081; 4,084,914 and 4,123,183). In other post constructions, deflectability is provided, in general, by segmenting the post and joining the post members using spring forces, which are readily overcome upon impact. Examples of these latter constructions may be found in U.S. Pat. Nos. 4,106,878; 4,092,081; 5,199,814; and 4,806,046. Although these spring-loaded constructions are made to deflect upon impact and often provide automatic restoration when the impact force is removed (sometimes described as self-upriding) various improvements are being sought. For example, due to the construction of the spring-loaded devices, their response to an impact force may depend upon the direction at which the impact is made to the post. Accordingly, posts with directional response must be oriented with respect to the direction of oncoming traffic and some measure of uncertainty as to the response of the device when struck from a different direction, must be taken into account. Further improvements are sought in simplifying the construction of such devices, which usually leads to cost reduction.
It is an object of the present invention to provide a vehicle barrier post fur use in roadside applications as well as applications on a roadway surface.
Another object of the present invention is to provide a vehicle barrier post of the above type which presents little or no practical resistance when impacted by a moving vehicle.
A further object of the present invention is to provide a post of the above-described type which is self-restoring after the impact-force is removed.
A further object of the present invention is to provide a vehicle barrier post of the above-described type which can be economically formed from a minimum number of inexpensive parts.
These and other objects of the present invention are provided in a deflectable sign mounting, comprising:
a tubular body, having upper and lower ends, for supporting the sign;
an extension spring secured within the tubular body;
a rocking base at the lower end of the tubular body;
said tubular body, said extension spring and said rocking base together comprising an upper assembly;
a stand-off member defining a hollow cavity and having upper and lower ends, the upper end of the standoff adapted for rocking engagement with the rocking base;
an elongated tether member having a second end secured to said deflectable sign mounting and a first end engaging said extension spring so as to hold said extension spring in tension;
a device base supporting said extension spring in an extended position, the device base defining an interior opening receiving the second end of the said elongated tether member;
a retainer member engaging the second end of said tether member so as to support the second end of the device base to maintain a predetermined tension in said extension spring; and
the rocking base and the upper end of the stand-off cooperating such that the upper assembly rocks about the stand-off upon application of a lateral force to the tubular body at a rest position, causing a bias energy to be stored within said extension spring, biasing the rocking base toward its rest position upon removal of the dislodging force.